Compound concrete is a mixture of coarsely-crushed concrete blocks and fresh concrete. The coarsely-crushed concrete blocks come from demolished buildings, and eventually have preferred size after a series of processing, e.g. breaking, screening and purifying process. This is a new technology in response to the environmental protection requirement in the country, developing green construction industry and realizing energy saving. However, it still faces difficulties as to how to use this technology effectively in practice.
In current engineering practice, a spacing between two adjacent stirrups in beams or two adjacent rebars in slabs is typically within 300 mm, but the demolished concrete block has a large size ranging from, say, 150 to 300 mm. These coarsely-crushed demolished concrete blocks thus cannot be placed into the rebar cage, particularly in regions with congested reinforcement. Owing to this, such technology has difficulty to be further applied. Alternatively, a conventional method can be used, that is, assembling bottom rebars into a cage first, then placing coarsely-crushed concrete blocks into the cage, followed by assembling top rebars eventually to close the cage. This construction method has a long construction period onsite, costing more time and labour.
Therefore, there is a need to have a construction method for producing beam/slab made of the compound concrete, the method can utilize the demolished concrete blocks, and is more simple, fast and reliable without any impact on the reinforcement configuration and force-carrying mechanism.